LPS (Lipopolysaccharide) is an endotoxin which exists as a critical glycolipid component of the outer cell wall of gram-negative bacteria. This compound is a known, potent initiator of the proinflammatory response and induces proinflammatory cytokines in several cell types. Many of the cell signals induced by gram-negative bacteria are attributed to LPS and have been observed to also activate TNF receptor signaling pathways. The major receptor that transduces the LPS signal has been recognized as a member of the Toll-like receptor family. At least 10 members of the family have been identified to date and TLR4 appears to be the main LPS receptor although coreceptors are most likely involved. Studies note that in HMEC (human microvascular endothelial cells) cell lines, LPS activates apoptosis pathways via both NF-κ B and JNK through TRAF6. Also reported that NF-κ B inhibition does not potentiate LPS-induced death in HMEC cells yet will sensitize these cell to TNF-induced death. Additional studies using HMEC cell lines report that following LPS stimulation, TRAF6 also transmits an important endothelial cell survival signal in a situation of complete NF-κ B blockade which may indicate that TRAF6 signals an NF-κ B–independent antiapoptotic pathway in endothelial cells exposed to LPS.

A mitogen for bone marrow derived B lymphocytes

For cell culture use, LPS should be reconstituted by adding 1 ml of sterile balanced salt solution or cell culture medium to a vial (1 mg) and swirling gently until the powder dissolves. Solutions can be further diluted to the desired working concentration with additional sterile balanced salt solution or cell culture medium. Storage/Stability: Solutions at 1 mg/ml in buffer or culture medium are stable for ~1 month at 2–8° C. Frozen aliquots can be stored up to 2 years. Repeated freeze/thaw cycles are not recommended. Solutions should be stored in silanized containers, since LPS can bind to plastics and certain types of glass (especially at concentrations of <0.1 mg/ml). If the LPS concentration is >1 mg/ml, adsorption to the sides of the vial is negligible. If glass containers are used, solutions should be vortexed for at least 30 minutes to redissolve the adsorbed product.

Store at 4° C,2 years.

LPS；Lipopolysaccharides from E. coli O111:B4; Bacterial lipopolysaccharides; Lipopolysaccharides

White to yellow lyophilized powder

Soluble in water (5 mg/ml), and cell culture medium (1 mg/ml).